The invention relates to an apparatus for applying a mask to and/or removing a mask from a preferably ring-shaped, flat substrate in a vacuum coating apparatus having two transport chambers arranged in planes parallel to one another which are connected to one another by a common opening.
An apparatus for coating flat substrates, compact disks for example, is known (U.S. Pat. No. 4,548,699) having a shallow cylindrical transport chamber and a circular disk-shaped substrate holder rotatably mounted in this transport chamber, which transports the substrate, after it is inserted through an airlock into the transport chamber, from the one treatment station to the next treatment station. The disk-shaped substrate holder is displaceable by a motor on the shaft on which it is rotatably mounted, also in the direction of the axis of rotation, so that the substrates disposed on the substrate plate are not only transportable on a circular path from station to station, but also can be moved to a point directly in front of the treatment station and to a point in front of the insertion and removal airlock opening in the chamber wall.
U.S. Pat. No. 3,915,117 discloses a vacuum coating apparatus for the vapor depositing of thin coatings on substrates, having an insertion chamber, additional chambers for the treatment and coating of the substrates, and an exit chamber provided with a conveying means disposed in an evacuable main chamber for carrying the substrates through the chambers, sealing means being provided for momentary sealing between the chambers and the main chamber. The conveying means having frames disposed about a common axis and swingable about this axis for holding the material that is to be coated, while in at least two treatment positions, namely an insertion and removal position and a vapor depositing position, such a frame itself forms a part of the wall of the treatment chamber, namely of the insertion and removal chamber and a vapor depositing chamber, and wherein a movable valve plate is provided in at least one of these treatment positions for shutting off one face of the frame forming a part of the treatment chamber.
Lastly, a vacuum coating apparatus is known (U.S. Pat. No. 3,838,028) in which, in addition to the cylindrical transport chamber for the circular disk-shaped rotatable substrate holder, a second chamber is provided for inserting and removing the substrates through an airlock, and is connected to the transport chamber through an opening.
The known vacuum coating apparatus all have the disadvantage that the application of masks to the substrates, intended to prevent the coating of the entire surface of the substrates, is possible only outside of the vacuum chamber and transport chamber. This, however, has the disadvantage especially that the masks for the partial covering of the substrates become unusable after just a few coating procedures, since after the coated substrates are removed through the exit airlock they come in contact with the oxygen of the air, resulting in a layer forming glitter on the surface of the mask.